Study On The Solar Ejector And Evaporation Coupled Cooling System

Solar energy,as a kind of inexhaustible natural resources,has the characteristics of safety,cleanness and cheapness.A large number of scholars and experts around the world began to apply solar energy to the field of air conditioning because of its reproducibility.However,solar refrigeration is limited by weather,so the coupling mode of the solar ejector refrigeration system and evaporative cooling system is proposed and the solar ejector and evaporation coupled cooling system is designed.In this paper,the structure forms of combination of solar ejector refrigeration and evaporative cooling are proposed and the combination mechanism and application range are studied.Firstly,the coupling system of solar ejector refrigeration system and evaporative cooling system is described in detail,and the thermodynamic analysis of the coupling system is carried out.The theoretical analysis of solar ejector refrigeration and evaporative cooling is carried out from the pressure-enthalpy diagram and enthalpy chart,respectively.The theoretical research on the cooling effect of two kinds of condensing methods of solar ejector refrigeration system shows that,the cooling capacity with use of evaporative condenser is indeed larger than the use of conventional condenser under the same condition.On the basis of theoretical research,the feasibility and application prospect of the two combinations are determined.Based on the climatic conditions in Xinjiang,Kashi,a model of coupled cooling system of solar ejector and evaporation is established.According to the adaptability of the cooling load of the simulation building and the design standard of the solar ejector and evaporative coupling cooling system,the solar ejector refrigeration system and the direct evaporative cooling system are designed.At the same time,the collector area,circulating water pump and heat storage tank volume and other equipment parameters are determined;The TRNSYS software is used to simulate the summer operation mode of the coupling system,simulate the cold load and other indoor parameters of the cold building,and determine the working control strategy of the system in the simulation process.That is,8: 00-12: 00 period,direct evaporative cooling is used for cooling,in the 13: 00-18: 00 period,solar ejector refrigeration is used for building cooling with the direct evaporative cooling system is used as the condenser of ejector refrigeration system.Comparative analysis between cooling capacity and building cooling load indicates that the combination of the two system can satisfy the user demand of the cold load,not only solve the problem of the limitation of environmental factors lead to the use of time,but also make the system reach the maximum energy saving.The COPm of direct evaporative cooling can reach 28,the maximum COPh of solar ejector refrigeration system is 0.18,and the maximum machinery COPm of solar ejector refrigeration machinery is 6.3.Based on the above simulation analysis method,the applicability and energy saving effect of solar ejector and evaporation coupled cooling system under different climatic conditions(dry area,medium humidity area and high humidity area)are analyzed under three typical weather days.According to the wet-bulb temperature of outdoor air in Guangzhou and Taiyuan and the design standard of comfortable air conditioning,the solar ejector and evaporation coupled cooling system in Guangzhou can only operate the solar ejector cooling mode that the direct evaporative cooling just act as a condenser of ejector refrigeration;The solar ejector and evaporation coupled cooling system in Taiyuan,8: 00-12: 00 operates direct evaporative cooling for room cooling,13: 00-18: 00 operates coupling system.The study on the solar ejector and evaporation coupled cooling system indicates that total power consumption of this system is about 52.46 k Wh in Kashi area during whole air conditioning season.Completely using a mechanical compression refrigeration system requires a power consumption of 172.5kWh.So this system consumes only 30.4% of the mechanical compression refrigeration system.In the Taiyuan area,using the coupling cooling system requires for the total power of 63.9k Wh during the air conditioning season.And it is about 152.7 kWh of power consumption using mechanical compression refrigeration system instead.The power consumption of coupled cooling system is only 42% of compression refrigeration.Both of them show a better effect of energy saving.